Poland e-Invoice QR and Readiness — connector documentation

MCP endpoint: https://pl-ksef-qr.connectorbay.com/mcp
REST API: POST https://pl-ksef-qr.connectorbay.com/v1/tools/{tool_name}, described by the OpenAPI 3.1 spec at https://pl-ksef-qr.connectorbay.com/openapi.json
Transport: Streamable HTTP, stateless, MCP specification 2025-06-18 or later
Authentication: none required. An optional Authorization: Bearer <key> raises rate limits.
Health: https://pl-ksef-qr.connectorbay.com/health · Tool schemas: https://pl-ksef-qr.connectorbay.com/tools.json
Publisher: Unify Dynamics LLC · connectorbay.com/pl-ksef-qr · agent@connectorbay.com

What Poland e-Invoice QR and Readiness is for

Poland e-Invoice QR and Readiness works with the National e-Invoice System (KSeF) verification codes and start dates. compute_invoice_hash gives the SHA-256 of the exact invoice XML bytes in Base64URL, as the QR link needs it. build_invoice_qr_url assembles the type I verification link (seller NIP, issue date, hash) for the production, demo or test host. build_certificate_qr_template assembles the type II offline-invoice link and the exact text that the owner's offline certificate must sign, with the signature parameters the documentation lists; it never signs anything. qr_label_text gives the text printed under each code. validate_nip checks the format and checksum of a Polish NIP. ksef_start_phase and days_until_ksef_deadline apply the published phase-in dates (1 February 2026, 1 April 2026, 1 January 2027) to the business's 2024 sales and monthly invoiced sales for a chosen date, and show whether the 2026 no-penalty period still runs. ksef_offline_modes_guide explains offline24, unavailability and emergency modes, their sending deadlines and which QR codes each carries. Everything is computed locally: no invoice is submitted, stored or signed, and no KSeF credentials are used. Independent tool; not affiliated with the Ministry of Finance or the KSeF operator. General information, not tax advice.

Ask your assistant things like:

"What is the verification QR link for my invoice from seller NIP 1111111111 issued 01-02-2026?"
"What hash of this invoice XML does the KSeF QR link need?"
"My 2024 sales were PLN 3 million and I invoice about PLN 50,000 a month: when must I start using KSeF?"
"How many days until my KSeF start date, and is the 2026 no-penalty period still running?"
"What text goes under each QR code of an offline invoice, and which offline modes need two codes?"
"What exact text must my offline certificate sign for the second QR code?"

What it does

compute_invoice_hash: SHA-256 of the invoice XML bytes as Base64URL (no padding), the hash segment of the KSeF QR link.
build_invoice_qr_url: KSeF type I verification link (seller NIP, issue date, invoice hash) for the production, demo or test host.
build_certificate_qr_template: KSeF type II (offline certificate) link template and the exact text to sign; never signs.
qr_label_text: Text printed under a KSeF QR code: the KSeF number, OFFLINE or CERTYFIKAT.
validate_nip: Polish NIP format and checksum check (no registry lookup).
ksef_start_phase: Which published KSeF start date (1 Feb 2026, 1 Apr 2026, 1 Jan 2027) applies to a business, from its 2024 sales and monthly invoiced sales.
days_until_ksef_deadline: Days to or since each KSeF milestone and whether the 2026 no-penalty period still applies on a date.
ksef_offline_modes_guide: The KSeF offline24, unavailability and emergency modes: when each applies, the sending deadline and the QR codes each carries.

Data sources

Reference data from official sources (github.com, gov.pl); every answer states its source, date and validity period.

What it is not

Poland e-Invoice QR and Readiness is independent; not affiliated with, endorsed by or operated by any government body, central bank, standards body or scheme operator. Names of rails, schemes and standards are used only to say what a tool works with. It is read-only: it never sends, pays, files or signs anything for you, and it never looks up private individuals.

Not advice. General information only, not legal, tax, accounting or payment advice. Poland e-Invoice QR and Readiness is an independent tool: it is not affiliated with, endorsed by or operated by any government body, central bank, standards body or scheme operator. Rates, thresholds and rules change; check the cited official source and confirm with a qualified professional before you rely on a result.

Built for: Poland. Languages: English.

Tools

Look up & validate

validate_nip — Polish NIP format and checksum check (no registry lookup). Use for "Is 1111111111 a well-formed Polish NIP?". It says nothing about whether the number belongs to an active taxpayer. Args: nip.

Calculate

compute_invoice_hash — SHA-256 of the invoice XML bytes as Base64URL (no padding), the hash segment of the KSeF QR link. Use for "What is the hash of this invoice XML in the format the KSeF QR link needs?". The hash covers the exact bytes you submit: any change of whitespace, line endings or encoding gives another hash. Args: invoice_xml, invoice_base64.

Build & format

build_invoice_qr_url — KSeF type I verification link (seller NIP, issue date, invoice hash) for the production, demo or test host. Use for "What is the KSeF verification QR link for the invoice of seller NIP 1111111111 issued on 01-02-2026 with this hash?". Args: seller_nip, issue_date, invoice_hash, environment, ksef_number.

build_certificate_qr_template — KSeF type II (offline certificate) link template and the exact text to sign; never signs. Use for "What exact text must my offline certificate sign for the second QR code of an offline invoice?". Args: context_type, context_value, seller_nip, certificate_serial, invoice_hash, environment, signature.

Reference & guides

qr_label_text — Text printed under a KSeF QR code: the KSeF number, OFFLINE or CERTYFIKAT. Use for "What text goes under the first and the second QR code of an offline invoice?". Args: qr_type, ksef_number.

ksef_start_phase — Which published KSeF start date (1 Feb 2026, 1 Apr 2026, 1 Jan 2027) applies to a business, from its 2024 sales and monthly invoiced sales. Use for "My 2024 sales were PLN 3,000,000 including VAT and I invoice up to PLN 50,000 a month: from when must I use KSeF?". Args: sales_2024_pln, max_monthly_invoiced_sales_pln, on_date.

days_until_ksef_deadline — Days to or since each KSeF milestone and whether the 2026 no-penalty period still applies on a date. Use for "How many days are left until KSeF applies to me and is the no-penalty period still running?". Args: sales_2024_pln, max_monthly_invoiced_sales_pln, on_date.

ksef_offline_modes_guide — The KSeF offline24, unavailability and emergency modes: when each applies, the sending deadline and the QR codes each carries. Use for "What is the difference between offline24, system unavailability and emergency mode, and which QR codes does each need?". Args: mode.

Conventions

Read-only. Every tool reads public data or computes; nothing is written anywhere and nothing about the user is stored.
Result envelope. ok: true with data, or ok: false with a structured error (bad_input, not_found, upstream_error). degraded lists optional sources that were unreachable.
Rate limits. Free tier 60 tool calls/minute and 300/day per user (keyed on the user identifier supplied by the host agent, else client IP); Pro keys raise this. Over-limit calls return HTTP 429 with Retry-After. initialize and tools/list are never counted.

Support

agent@connectorbay.com · connectorbay.com/pl-ksef-qr/support